Bonded semiconductor structures and method of forming same

ABSTRACT

Methods of forming semiconductor structures include transferring a portion ( 116   a ) of a donor structure to a processed semiconductor structure ( 102 ) that includes at least one non-planar surface. An amorphous film ( 144 ) may be formed over at least one non-planar surface of the bonded semiconductor structure, and the amorphous film may be planarized to form one or more planarized surfaces. Semiconductor structures include a bonded semiconductor structure having at least one non-planar surface, and an amorphous film disposed over the at least one non-planar surface. The bonded semiconductor structure may include a processed semiconductor structure and a portion of a single crystal donor structure attached to a non-planar surface of the processed semiconductor structure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a national phase entry under 35 U.S.C. §371 of InternationalPatent Application PCT/U.S.2011/025647 filed Feb. 22, 2011, whichapplication claims the benefit of the filing date of U.S. ProvisionalPatent Application Ser. No. 61/319,495, filed Mar. 31, 2010, for “BONDEDSEMICONDUCTOR STRUCTURES AND METHOD OF FORMING SAME,” the disclosure ofeach of which is hereby incorporated herein by this reference in itsentirety.

TECHNICAL FIELD

Embodiments of the present invention generally relate to methods forforming semiconductor structures and to the resulting structures formedusing such methods and, more particularly, to bonded semiconductorstructures and methods of forming the same.

BACKGROUND

The three-dimensional (3D) integration of two or more semiconductorstructures can produce a number of benefits to microelectronicapplications. For example, 3D integration of microelectronic componentscan result in improved electrical performance and power consumptionwhile reducing the area of the device footprint. See, for example, P.Garrou, et al. “The Handbook of 3D Integration,” Wiley-VCH (2008).

The 3D integration of semiconductor structures may be achieved by anumber of methods, including, for example, the transfer of one or moresemiconductor layers to a processed semiconductor structure, which mayinclude a plurality of device structures. The transfer of asemiconductor layer to a processed semiconductor structure may beachieved by transferring a portion of a donor structure to the processedsemiconductor structure using, for example, methods such as, ionimplantation, bonding, and separation. The transferred portion of thedonor structure may undergo further processes, for example, to produceadditional device structures therein, which may be integrated withunderlying device structures. However, the processes involved in formingthe processed semiconductor structure and in the transfer of a portionof the donor structure to the processed semiconductor structure maydetrimentally affect the quality of the bonded semiconductor structure.

It should be noted that the 3D integration of semiconductor structuresmay take place by the attachment of a semiconductor die to one or moreadditional semiconductor dies (i.e., die-to-die (D2D)), a semiconductordie to one or more semiconductor wafers (i.e., die-to-wafer (D2W)), aswell as a semiconductor wafer to one or more additional semiconductorwafers (i.e., wafer-to-wafer (W2W)), or a combination thereof.

BRIEF SUMMARY

Embodiments of the present invention may provide methods and structuresfor forming semiconductor structures, and more particularly, methods andstructures for forming bonded semiconductor structures. This summary isprovided to introduce a selection of concepts in a simplified form thatare further described in the detailed description of embodiments of theinvention. This summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter.

Therefore, in some embodiments of the present invention, methods offorming a semiconductor structure may include transferring a portion ofa donor structure to a processed semiconductor structure and forming abonded semiconductor structure comprising one or more non-planarsurfaces. An amorphous film may be formed over at least the one or morenon-planar surfaces of the bonded semiconductor structure, and theamorphous film may be planarized to form one or more planarizedsurfaces. Planarizing the amorphous film may comprise removing a portionof the amorphous film outside at least one recess in the one or morenon-planar surfaces, and leaving a portion of the amorphous film withinthe at least one recess in the one or more non-planar surfaces.

In additional embodiments of the invention, methods of forming asemiconductor structure may include forming a plurality of devicestructures on or in a semiconductor structure to produce a processedsemiconductor structure comprising a non-planar major surface and anon-planar lateral side surface. A portion of a donor structure at leastsubstantially comprised by a single crystal of semiconductor materialmay be transferred to the non-planar major surface of the processedsemiconductor structure to form a bonded semiconductor structure havinga non-planar major surface and a non-planar lateral side surface. Anamorphous film may be formed over the non-planar lateral side surfaceand the non-planar major surface of the bonded semiconductor structure,and at least the non-planar major surface of the bonded semiconductorstructure may be planarized by selectively removing portions of theamorphous film.

Embodiments of the invention may also include semiconductor structuresformed by methods described herein. In some embodiments of theinvention, a semiconductor structure includes a bonded semiconductorstructure having a non-planar major surface and a non-planar lateralside surface, and an amorphous film disposed over the non-planar lateralside surface and the non-planar major surface of the bondedsemiconductor structure. The bonded semiconductor structure may includea processed semiconductor structure comprising a non-planar majorsurface and a non-planar lateral side surface, and a portion of a singlecrystal donor structure attached to the non-planar major surface of theprocessed semiconductor structure.

In some embodiments of the invention, a semiconductor structurecomprises a bonded semiconductor structure having a non-planar majorsurface and a non-planar lateral side surface, and a plurality ofregions of recrystallized crystalline material disposed over valleyregions of the non-planar lateral side surface and the non-planar majorsurface of the bonded semiconductor structure. The bonded semiconductorstructure may include a processed semiconductor structure comprising aplurality of device structures, a non-planar major surface, and anon-planar lateral side surface. The bonded semiconductor structure mayalso include a portion of a single crystal donor structure attached tothe non-planar major surface of the processed semiconductor structure.Further aspects, details, and alternate combinations of elements ofadditional embodiments of this invention will be apparent from thefollowing detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention may be understood more fully byreference to the following detailed description of embodiments of thepresent invention, illustrative examples of specific embodiments of theinvention, and the appended figures in which:

FIGS. 1A-1G schematically illustrate example embodiments of theinvention for forming bonded semiconductor structures.

FIGS. 2A-2F schematically illustrate additional example embodiments ofthe invention for forming bonded semiconductor structures.

DETAILED DESCRIPTION OF THE INVENTION

The illustrations presented herein are not meant to be actual views ofany particular material, apparatus, system, or method, but are merelyidealized representations that are employed to describe embodiments ofthe present invention.

Headings are used herein for clarity only and without any intendedlimitation. A number of references are cited herein. None of the citedreferences, regardless of how characterized herein, is admitted as priorart relative to the invention of the subject matter claimed herein.

As used herein, the term “semiconductor structure” means and includesany structure comprising a semiconductor material and that is used inthe formation of a semiconductor device. Semiconductor structuresinclude, for example, bulk semiconductor material bodies such assemiconductor dies and wafers, as well as assemblies or compositestructures that include a layer or region of semiconductor material andone or more other materials such as metals and/or insulators thereon.Semiconductor structures also include fully fabricated semiconductordevices, as well as intermediate structures formed during fabrication ofsemiconductor devices.

As used herein, the term “processed semiconductor structure” means andincludes any semiconductor structure that includes one or more at leastpartially formed device structures.

As used herein, the term “device structure” means and includes anyportion of a semiconductor structure that is, includes, or defines atleast a portion of an active or passive component of a semiconductordevice to be formed from the semiconductor structure. For example,device structures include active and passive components of integratedcircuits such as, for example, transistors, transducers, capacitors,resistors, conductive lines, conductive vias, and conductive contactpads.

As used herein, the term “bonded semiconductor structure” means andincludes any structure that includes two or more semiconductorstructures that are attached together.

Embodiments of the invention comprise methods and structures for formingsemiconductor structures and, more particularly, to semiconductorstructures that include bonded semiconductor structures and methods offorming such semiconductor structures. The bonded semiconductorstructures may include a processed semiconductor structure that includesa plurality of device structures and a transferred portion of a donorstructure carried by (e.g., bonded to) the processed semiconductorstructure. The bonded structure may also include one or more non-planarsurfaces, and embodiments of the invention may include the planarizationof the one or more non-planar surfaces and the formation of anadditional number of device structures within the planarized surfaces.Such additional device structures may be electrically interconnectedwith the device structures of the processed semiconductor structure.Such methods and structures may be utilized for various purposes, suchas, for example, for 3D integration processes and 3D integratedstructures.

Example embodiments of the invention are described below with referenceto FIGS. 1A-1G. FIG. 1A illustrates a processed semiconductor structure100. Processed semiconductor structure 100 may include a number ofdevice structures 104 and one or more non-planar surfaces such as, forexample, a non-planar major surface 106 (e.g., a top surface) and anon-planar lateral side surface 108.

In greater detail, embodiments of the invention may proceed by forming aprocessed semiconductor structure 100 comprising one or more non-planarsurfaces. The one or more non-planar surfaces may include a non-planarmajor surface 106 and a non-planar lateral side surface 108. Formingprocessed semiconductor structure 100 may comprise fabricating a numberof device structures 104 in a semiconductor structure 110. The number ofdevice structures 104 may comprise, for example, one or more ofswitching structures (e.g., transistors, etc.), light-emittingstructures (e.g., laser diodes, light-emitting diodes, etc.),light-receiving, emitting, or guiding structures (e.g., waveguides,splitters, mixers, photodiodes, solar cells, solar subcells, etc.), andmicroelectromechanical system structures (e.g., accelerometers, pressuresensors, etc).

Methods for fabricating the number of device structures 104 may resultin processed semiconductor structure 100 including a non-planar majorsurface 106 and a non-planar lateral side surface 108. The topology ofthe non-planar surfaces 106 and 108 may comprise a plurality of peakregions 112 and a plurality of valley regions 114. Methods forfabricating the number of device structures 104 may comprise, forexample, one or more of lithography, etching, cleaning, ionimplantation, bonding, deposition, handling and metallization.

The processed semiconductor structure 100 may comprise a number oflayers and materials. Processed semiconductor structure 100 may comprisesemiconductor materials, such as, for example, one or more of silicon,germanium, silicon carbide, III-arsenides, III-phosphides, III-nitrides,and III-antimonides. The processed semiconductor structure 100 may alsoinclude non-semiconductor materials utilized in conjunction withsemiconductor materials for the fabrication of device structures.Non-semiconductor materials utilized in conjunction with semiconductormaterials may include conducting materials (e.g., metallic materials),such as, for example, one or more of cobalt, ruthenium, nickel,tantalum, tantalum nitride, indium oxide, tungsten, tungsten nitride,titanium nitride, copper and aluminum. In addition, non-semiconductormaterials utilized in conjunction with semiconductor materials mayinclude insulating materials (e.g., dielectric materials), such as, forexample, one or more of polyimides, benzocyclobutene (BCB), boronnitrides, boron carbide nitrides, porous silicates, silicon oxides,silicon nitrides, other oxides, other nitrides, and mixtures thereof.

Referring to FIG. 1B, a portion of a donor structure 116 may betransferred to the non-planar major surface 106 of the processedsemiconductor structure 100. A transferred portion of the donorstructure 116 may be utilized for the fabrication of additional devicestructures, which may be electrically interconnected to devicestructures 104 of processed semiconductor structure 100, as discussed infurther detail below.

FIG. 1B illustrates a bonded semiconductor structure 118, whichcomprises processed semiconductor structure 100 and donor structure 116.Donor structure 116 may comprise materials and structures as describedfor processed semiconductor structure 100. In some embodiments, donorstructure 116 may comprise a single crystal of a semiconductor material,which may be selected from, for example, silicon, germanium, siliconcarbide, III-arsenides, III-phosphides, III-nitrides, andIII-antimonides.

To transfer a portion of donor structure 116 to the non-planar majorsurface 106 of processed semiconductor structure 100, a surface 120 ofdonor structure 116 may be attached to the non-planar major surface 106of processed semiconductor structure 100.

Donor structure 116 may be attached to processed semiconductor structure100 using, for example, a bonding process along a discontinuous bondinginterface 122 between the non-planar major surface 106 of the processedsemiconductor structure 100 and an adjacent surface 120 of the donorstructure 116. For further information on the bonding of semiconductorstructures, see, for example, the journal publications of Tong et al.,Materials, Chemistry and Physics 37 101 1994, entitled “Semiconductorwafer bonding: recent developments,” and Christiansen et al.,Proceedings of the IEEE 94 12 2060 2006, entitled “Wafer Direct Bonding:From Advanced Substrate Engineering to Future Applications inMicro/Nanoelectronics.”

The topology of non-planar major surface 106 may result in the formationof a discontinuous bonding interface 122 between the donor structure 116and the non-planar major surface 106 of the processed semiconductorstructure 100. Such a discontinuous bonding interface 122 may comprise anumber of bonded regions 124 and a number of unbonded regions 126. Thebonded regions 124 of discontinuous bonding interface 122 may comprisepeak regions 112 of the non-planar major surface 106 of processedsemiconductor structure 100 bonded to surface 120 of donor structure116, and the unbonded regions 126 of discontinuous bonding interface 122may comprise valley regions 114 of the non-planar major surface 106 ofprocessed semiconductor structure 100.

Upon attachment of donor structure 116 to the non-planar major surface106 of processed semiconductor structure 100, the donor structure 106may be thinned to reduce a thickness of the attached donor structure 116to a value desirable for subsequent processes (e.g., for the fabricationof device structures within a portion of the donor structure 116).

In greater detail, donor structure 116 may be thinned such that aportion of donor structure 116 a is carried by (e.g., attached to)processed semiconductor structure 100, and a remaining portion of donorstructure 116 b is not carried by processed semiconductor structure 100.The donor structure 116 may be thinned by removing material from thedonor structure 116 on a side thereof opposite the non-planar majorsurface 106. The thinning of donor structure 116 may be performedutilizing any of a number of methods, such as, for example, one or moreof etching, polishing, grinding, laser lift-off, and chemical-mechanicalpolishing.

As another non-limiting example, processes known in the industry asSMART-CUT™ processes may be used to thin donor structure 116. Suchprocesses are described in detail in, for example, U.S. Pat. No.RE39,484 to Bruel (issued Feb. 6, 2007), U.S. Pat. No. 6,303,468 toAspar et al. (issued Oct. 16, 2001), U.S. Pat. No. 6,335,258 to Aspar etal. (issued Jan. 1, 2002), U.S. Pat. No. 6,756,286 to Moriceau et al.(issued Jun. 29, 2004), U.S. Pat. No. 6,809,044 to Aspar et al. (issuedOct. 26, 2004), and U.S. Pat. No. 6,946,365 to Aspar et al. (Sep. 20,2005).

Briefly, in accordance with such embodiments, the donor structure 116may be thinned by implanting ions 128 into the donor structure 116through a surface thereof to from a zone of weakness 130 within thedonor structure 116. The zone of weakness 130 within the donor structure116 may be formed prior to bonding the donor structure 116 to theprocessed semiconductor structure 100.

Upon formation of the zone of weakness 130 and after attaching donorstructure 116 to the processed semiconductor structure 100 to formbonded semiconductor structure 118, the temperature of semiconductorstructure 118 may be heated to and maintained at an elevated temperature(e.g., above about 100° C.) for an amount of time sufficient to causethe implanted ions within zone of weakness 130 to coalesce and form aplurality of microcavities and/or inclusions within the donor structure116. Additional energy then may be supplied to the donor structure 116to promote fracture of donor structure 116 generally along the zone ofweakness 130, such that the portion 116 b of the donor structure 116becomes separated from the portion 116 a of the donor structure 116 andthe processed semiconductor structure 100.

FIG. 1C illustrates bonded semiconductor structure 132, which comprisesprocessed semiconductor structure 100 and a portion of donor structure116 a carried by processed semiconductor structure 100 via discontinuousbonding interface 122. Due to the presence of unbonded areas 126 betweendonor structure 116 and processed semiconductor structure 100 (see FIG.1B), the bond strength there between may be insufficient to result in aclean, planar fracture along the zone of weakness 130. As a result, adiscontinuous portion of donor structure 116 a may be transferred to andcarried by processed semiconductor structure 100. In other words, duringthe fracturing process, the unbonded areas 126 between donor structure116 and processed semiconductor structure 100 may prevent fracture atthe zone of weakness 130 in the vicinity of the unbounded areas 126,such that the fracture surface is non-planar and extends along the zoneof weakness in some areas, but along the unbounded areas 126 in otherareas. The incomplete transfer of a portion of donor structure 116 a toprocessed semiconductor structure 100 may result in the bondedsemiconductor structure 132 having a non-planar major surface 134, asshown in FIG. 1C.

In greater detail, the topology of non-planar major surface 134comprises a plurality of peak regions 136 and a plurality of valleyregions 138. A plurality of recesses 140, which correspond to thevolumes of space previously occupied by portions of the donor structure116 that were not transferred to the processed semiconductor structure100 as intended, may be disposed over and extend to the plurality ofvalley regions 138 (i.e., low lying regions of the non-planar majorsurface 134). In contrast, a portion or portions of donor structure 116a transferred to processed semiconductor 102 comprise or define theplurality of peak regions 136. The maximum peak-to-valley distance maybe defined as the maximum vertical distance between the lowest lyingvalley region 138 and the highest lying peak region 136. For example,the inset of FIG. 1C illustrates a lowest lying valley region 138′ and ahighest lying peak region 136′ of the non-planar major surface 134. Thevertical distance between peak region 136′ and valley region 138′ may bedefined as the maximum peak-to-valley distance PV_(max).

FIG. 1D illustrates a bonded semiconductor structure 142 that comprisesan amorphous film 144 formed over the bonded semiconductor structure 132of FIG. 1C. Amorphous film 144 overlays the bonded semiconductorstructure 132 including over the non-planar major surface 134 and thenon-planar lateral side surface 108. Amorphous film 144 has an averagethickness D₁ and may comprise one or more layers of amorphous material.Such amorphous materials may include, for example, one or more ofsilicon, germanium, silicon carbide, a III-arsenide material, aIII-phosphide material, a III-nitride material, and a III-antimonidematerial.

Amorphous film 144 may be formed over all or a portion of non-planarmajor surface 134 and non-planar lateral side surface 108 utilizing anyof a number of methods. For example, amorphous film 144 may be formedutilizing a deposition method, such as, for example, chemical vapordeposition (CVD). A number of CVD methods are known in the art and maybe used to produce the amorphous film 144. Such CVD methods may includeone or more of atmospheric pressure CVD (APCVD), low-pressure CVD(LPCVD) and ultra-high vacuum CVD (UHCVD). In some embodiments of theinvention, the amorphous film 144 may be formed utilizing lowtemperature CVD methods. Such methods may include, for example, one ormore of LPCVD and plasma-assisted CVD methods, such as, for example,sub-atmospheric CVD (SACVD), microwave plasma-assisted CVD (MPCVD),plasma-enhanced CVD (PECVD) and remote plasma-enhanced CVD (RPECVD).LPCVD and plasma-assisted CVD methods for deposition of the amorphousfilm 144 may be utilized in some embodiments of the invention to providea low temperature deposition process.

A low temperature deposition process may be utilized in order to preventdegradation of the device structures 104 present in processedsemiconductor structure 100. Therefore, in some embodiments of theinvention, amorphous film 144 may be formed at a temperature of lessthan about 400° C. In additional embodiments of the invention, theamorphous film 144 may be formed at a temperature less than about 500°C., whereas in yet further embodiments of the invention, the amorphousfilm 144 may be formed at a temperature less than about 600° C.

As illustrated in FIG. 1D, amorphous film 144 may be depositedconformally over the non-planar major surface 134 and the non-planarlateral side surface 108 of bonded semiconductor structure 132.Conformal deposition of amorphous film 144 may be utilized to plug(i.e., at least substantially fill) the plurality of recesses 140 ofnon-planar major surface 134 and the plurality of recesses disposed overthe valley regions 114 of non-planar lateral side surface 108. However,the use of a conformal deposition process to plug recesses in thenon-planar surfaces of bonded semiconductor structure 132 may result inthe amorphous film 144 itself having non-planar surfaces, such as anon-planar major surface 146 on a side of the amorphous film 144opposite the processed semiconductor structure 100, since the conformalfilm may have a thickness D₁ that is substantially uniform throughoutthe amorphous film 144. In other words, the amorphous film 144 may bedeposited in such a way that the material of amorphous film 144substantially preserves the topography of the underlying non-planarsurfaces of the bonded semiconductor structure 132 of FIG. 1C.

In some embodiments of the invention, the amorphous film 144 may have anaverage thickness D₁ that is greater than the maximum peak-to-valleydistance PV_(max) of the non-planar surfaces of the bonded semiconductorstructure 132 of FIG. 1C. The thickness D₁ may be selected to be greaterthan PV_(max) so that a plurality of the recesses 140 and a plurality ofthe recesses overlying the valley regions 114 may be at leastsubstantially plugged by the amorphous film 144.

FIG. 1E illustrates bonded semiconductor structure 148, which comprisesthe bonded semiconductor structure 132 of FIG. 1C, and may be formed byplanarizing one or more surfaces of the amorphous film 144 of the bondedsemiconductor structure 142 of FIG. 1D. Thus, the bonded semiconductorstructure 148 of FIG. 1E includes one or more planarized surfaces,including, for example, planarized major surface 134′. In greaterdetail, amorphous film 144 may be processed in such a way that thenon-planarity of amorphous film 144 is substantially removed, resultingin one or more planarized surfaces (e.g., planarized bonded surface134′). The planarized bonded surface 134′ comprises a portion of donorstructure 116 a and remaining portions of amorphous film 144′.

A number of methods may be utilized to planarize the amorphous film 144to form one or more planarized surfaces. For example, the planarizationprocess may be performed utilizing one or more of an etching process, agrinding process and a polishing process. In some embodiments of theinvention, the planarization process may be performed utilizing achemical-mechanical polishing (CMP) process. The CMP process conditions,in particular the slurry abrasives and chemistry, may be chosen so thatthe non-planarity of the amorphous film 144 is reduced in such a manneras to provide one or more of a planarized major surface 134′ and aplanarized lateral side surface 108′. In some embodiments of theinvention, a portion of the amorphous film 144 may be selectivelyremoved (e.g., by CMP methods) such that remaining portions of amorphousfilm 144′ are disposed in the plurality of recesses 140 and in theplurality of recesses disposed over the valley regions 114, as shown inFIG. 1E.

FIG. 1F illustrates a bonded semiconductor structure 150, whichcomprises bonded semiconductor structure 132, a portion of donorstructure 116 a, and regions of recrystallized material 144″. Theregions of recrystallized material 144″ may be formed by thermallytreating and recrystallizing the remaining portions of amorphous film144′ that are disposed in the plurality of recesses 140 and in theplurality of recesses disposed over the valley regions 114 in the bondedsemiconductor structure 148 of FIG. 1E.

In some embodiments of the invention, remaining portions of amorphousfilm 144′ may be thermally treated by a heating process, wherein theheating process raises the temperature of remaining portions ofamorphous film 144′ to a temperature at least sufficient to promoterecrystallization in the amorphous material. Heating of remainingportions of amorphous film 144′ to a temperature at least sufficient topromote recrystallization in the amorphous material may form a number ofregions of recrystallized material 144″. The regions of recrystallizedmaterial 144″ may comprise one or more of, for example, volumes ofnanocrystalline material, volumes of polycrystalline material, andsingle crystals.

A number of methods may be utilized for the formation of the regions ofrecrystallized material 144″. By way of example and not limitation, theremaining portions of amorphous film 144′ may comprise amorphoussilicon, and the thermal treatment may comprise one or more of laserannealing, infrared lamp heating, rapid thermal annealing and electricalcurrent-induced joule heating. In some embodiments, the portion of donorstructure 116 a may be at least substantially comprised of a singlecrystal of material, which may act as a seed material to the remainingportions of amorphous film 144′ during recrystallization, such that theatoms of the amorphous film 144′ become incorporated to and part of thesingle crystal of the donor structure 116 a. In such embodiments, theremay be no identifiable boundary between the regions of recrystallizedmaterial 144″ and the donor structure 116 a.

Device structures 104 present within processed semiconductor structure100 may be damaged if the thermal treatment of the recrystallizationprocess is performed at a temperature above a critical temperature forthe onset of device degradation. Therefore, in some embodiments of theinvention, heating of the remaining portions of amorphous film 144′ to atemperature at least sufficient to promote recrystallization in thematerial is performed at a temperature of less than about 400° C. Inadditional embodiments, heating of the remaining portions of amorphousfilm 144′ for recrystallization is performed at a temperature less thanabout 500° C., whereas in yet further embodiments of the invention,heating of the remaining portions of amorphous film 144′ forrecrystallization is performed at a temperature less than about 600° C.

Upon heating the remaining portions of amorphous film 144′ to atemperature sufficient to promote recrystallization of the amorphousmaterial, the temperature of the bonded semiconductor structure 150 isreduced. The resulting bonded semiconductor structure 150 may compriseone or more of single crystal, nanocrystalline and polycrystallinematerials and may comprise a substantially planar major surface 134″. Insome embodiments, such a semiconductor structure may be suitable for thefabrication of additional device structures within the portion of donorstructure 116 a (including within the regions of recrystallized material144″).

FIG. 1G illustrates bonded semiconductor structure 152, which may beformed by fabricating additional device structures 154 within theportion of donor structure 116 a (including within the regions ofrecrystallized material 144″) of the bonded semiconductor structure 150of FIG. 1F. The device structures 154 formed within the portion of donorstructure 116 a (including within the regions of recrystallized material144″) may be electrically interconnected to device structures 104 withinthe processed semiconductor structure 100 using electrically conductiveinterconnects 156, as shown in FIG. 1G. The interconnects 156 maycomprise, for example, conductive vias.

The additional device structure 154 may be formed utilizing methodssimilar to those described for forming the device structures 104. Aspreviously described for processed semiconductor structure 100, thefabrication of additional device structures 154 to form the bondedsemiconductor structure 152 of FIG. 1G may result in the formation ofone or more non-planar surfaces in the bonded semiconductor structure152, such as, for example, a non-planar major surface 158 and anon-planar lateral side surface 160.

Fabrication of additional device structures 154 may include theformation of interconnects 156. The interconnects may provide a routefor interconnection between the device structures 104 in processedsemiconductor structure 100 and the additional device structures 154.

Additional embodiments of the invention are described below withreference to FIGS. 2A-2E. The embodiments illustrated in FIGS. 2A-2E aresimilar to those previously described with reference to FIGS. 1A-1G.However, in the embodiments of FIGS. 2A-2E, an additional donorstructure is attached to the bonded semiconductor structure 152 (of FIG.1G) formed utilizing the methods of FIGS. 1A-1G. The materialtransferred from the additional donor structure to semiconductorstructure 152 may undergo further processes for the fabrication ofadditional device structures therein. The additional device structuresmay be interconnected to the device structures of the bondedsemiconductor structure 152, thereby producing another 3D integratedstructure.

Embodiments of the invention described with reference to FIGS. 2A-2E maycommence with bonded semiconductor structure 152 of FIG. 1G. Bondedsemiconductor structure 152 includes one or more non-planar surfaces,including, for example, non-planar major surface 158 and non-planarlateral side surface 160. FIG. 2A illustrates bonded semiconductorstructure 218, which may be formed by attaching another donor structure216 to the bonded semiconductor structure 152 (of FIG. 1G). Bondedsemiconductor structure 152 and the additional donor structure 216 maybe attached to one another along a discontinuous bonding interface 222.The non-planar major surface 158 of the bonded semiconductor structure152 may be attached to a surface 220 of donor structure 216.

The donor structure 216 may be thinned in a manner like that previouslydiscussed in relation to the donor structure 116. For example, ions 228may be implanted into the donor structure 216 to form a zone of weakness230 therein. The donor structure 116 then may be fractured along thezone of weakness 230 to thin the donor structure 216 to a desiredthickness.

FIG. 2B illustrates a bonded semiconductor structure 232 that includesthe bonded semiconductor structure 218 of FIG. 2A, after thinning donorstructure 216 such that a portion of donor structure 216 a is carried bybonded semiconductor structure 218. The portion of donor structure 216 aand a plurality of non-transferred regions 240 may result in theformation of non-planar major surface 234 on the bonded semiconductorstructure 232.

FIG. 2C illustrates another bonded semiconductor structure 242 that maybe formed by forming amorphous film 244 over the bonded semiconductorstructure 232 of FIG. 2B. The amorphous film 244 may be formed usingmethods previously described. Amorphous film 244 may include non-planarmajor surface 246.

Upon formation of amorphous film 244, the amorphous film 244 may beplanarized to form one or more planarized surfaces, such as, forexample, a planarized major surface 234′ of the bonded semiconductorstructure 248 as shown in FIG. 2D. Formation of one or more planarizedsurfaces may include, for example, utilizing methods such as thosepreviously mentioned. For example, a chemical-mechanical polishingprocess may be used to planarize the amorphous film 244.

The remaining portions of amorphous film 244′ may be thermally treated(as shown in FIG. 2D). For example, the remaining portions of amorphousfilm 244′ may be subjected to a thermal treatment comprising a heatingprocess in which the remaining portions of the amorphous film 244′ maybe heated to a temperature sufficient to promote recrystallization ofthe amorphous film, thereby forming a number of regions ofrecrystallized material 244″ as shown in FIG. 2E. Thus, the bondedsemiconductor structure 250 shown in FIG. 2E may include a planarizedmajor surface 234′ comprising a portion of donor structure 216 a and anumber of regions of recrystallized material 144″.

FIG. 2F illustrates a bonded semiconductor structure 252 that may beformed by fabricating additional device structures 204 in the portion ofdonor structure 216 a and the regions of recrystallized material 144″.The additional device structures 204 may overlay the device structures154, which may in turn overlay the device structures 104. A plurality ofinterconnects 256 and 156 may be formed between the device structures204, the device structures 154 and the device structure 104, therebyforming a plurality of interconnected device structures within thebonded semiconductor structure 252.

It should be appreciated that yet further donor structure(s) may beattached and processed according to the embodiments of the invention tofabricate bonded semiconductor structures comprising additional devicestructures, wherein the device structures of each individual processedsemiconductor structure may be interconnected to device structures ofother processed semiconductor structures of the bonded semiconductorstructures.

EXAMPLE

A non-limiting example embodiment of the invention is set forth below.It should be understood that, in the following example, parameters(e.g., materials, structures, etc.) are for illustrative purposes only,and do not limit embodiments of the present invention.

With reference to FIG. 1A, a processed semiconductor structure 100comprises a complementary metal oxide semiconductor (CMOS) structureincluding a plurality of transistor device structures 104.CMOS-processed semiconductor structure 100 may be fabricated from asemiconductor structure 110 comprising a single crystal of silicon, inaddition to non-semiconductor materials such as silicon oxide, siliconnitrides and metallic materials. The processes used to fabricate theCMOS-processed semiconductor structure 100 include, for example, etchingprocesses, deposition processes, lithography processes and handlingprocesses. Such processes result in non-planar major surface 106 andnon-planar lateral side surface 108.

A donor structure 116 (as shown in FIG. 1B) comprising a single crystalsilicon substrate is provided. Silicon donor structure 116 is implantedwith ions, such as, for example, one or more of hydrogen, helium, andnitrogen ions, to form a zone of weakness 130 within the silicon donorstructure 116. The silicon donor structure 116 including the zone ofweakness 130 is attached by a bonding process to the CMOS-processedsemiconductor structure 100.

The bonding process may include the deposition of one or more bondassisting layers (not shown) upon one or both bonding surfaces. Forexample, bond-assisting layers may be provided upon at least one of thesurface 120 of silicon donor structure 116 and the non-planar majorsurface 106 of CMOS-processed semiconductor structure 100. The bondingprocess includes placing non-planar major surface 106 of theCMOS-processed semiconductor structure 100 in intimate contact withsurface 120 of the silicon donor structure 116. Further pressure andthermal processes are applied to improve the bond strength between thebonding structures.

Upon attaching CMOS-processed semiconductor structure 100 to silicondonor structure 116, further thermal energy is supplied to promotefracture and separation of the silicon donor structure along the zone ofweakness 130. Due to the non-planar major surface 106 of CMOS-processedsemiconductor structure 100, a discontinuous portion of silicon donorstructure 116 a is transferred and carried by CMOS-processedsemiconductor structure 100 (as shown in FIG. 1C), resulting in theformation of bonded semiconductor structure 132. A non-planar majorsurface 134 is formed, which includes a portion of silicon donorstructure 116 a and recesses 140.

An amorphous silicon film 144 is deposited over the bonded semiconductorstructure 132 utilizing a low-pressure chemical vapor deposition (LPCVD)process and silane gas (SiH₄) as a precursor at a temperature of lessthan 400° C. Amorphous silicon film 144 is deposited to an averagethickness D₁, such that recesses 140 and recesses over valley regions114 are plugged with amorphous silicon film 144 (as shown in FIG. 1D). Achemical mechanical polishing process is subsequently utilized toplanarize the surface 146 of the amorphous silicon film 144, and toselectively remove the non-planarity of the amorphous silicon film 144and produce planarized major surface 134′, as shown in FIG. 1E.

Bonded semiconductor structure 148 (of FIG. 1E) is subjected to aheating process to anneal the bonded semiconductor structure 148 at atemperature of less than 500° C. The annealing process is used topromote recrystallization of the remaining portions of amorphous siliconfilm 144″ and the formation of a plurality of regions of recrystallizedsilicon 144″. Subsequent processes repeat fabricating processes utilizedfor formation of CMOS-processed semiconductor structure 100 to fabricateadditional device structures 154, including additional transistors. Thefabrication process includes the formation of a number of interconnects156, such that device structures 154 are interconnected with devicestructures 104, thereby forming a 3D integrated structure.

Additional non-limiting example embodiments of the disclosure aredescribed below.

Embodiment 1: A method of forming a semiconductor structure comprising:

-   -   transferring a portion of a donor structure to a processed        semiconductor structure and forming a bonded semiconductor        structure comprising one or more non-planar surfaces;    -   forming an amorphous film over at least the one or more        non-planar surfaces of the bonded semiconductor structure; and    -   planarizing the amorphous film to form one or more planarized        surfaces comprising:        -   removing a portion of the amorphous film outside at least            one recess in the one or more non-planar surfaces; and        -   leaving a portion of the amorphous film within the at least            one recess in the one or more non-planar surfaces.

Embodiment 2: The method of Embodiment 1, wherein transferring theportion of the donor structure to the processed semiconductor structurecomprises:

-   -   bonding the portion of the donor substrate to a non-planar        surface of the processed semiconductor structure along a        discontinuous bonding interface therebetween; and    -   thinning the donor structure by removing material from the donor        structure on a side thereof opposite the non-planar surface of        the processed semiconductor structure.

Embodiment 3: The method of Embodiment 2, wherein thinning the donorstructure further comprises:

-   -   implanting ions into the donor structure to faun a zone of        weakness within the donor structure; and    -   fracturing the donor structure at the zone of weakness and        detaching another portion of the donor structure from the        portion of the donor structure bonded to the non-planar surface        of the processed semiconductor structure.

Embodiment 4: The method of any one of Embodiments 1 through 3, whereintransferring the portion of the donor structure to the processedsemiconductor structure comprises transferring discontinuous portions ofthe donor structure to the processed semiconductor structure.

Embodiment 5: The method of any one of Embodiments 1 through 4, whereinforming the amorphous film over at least the one or more non-planarsurfaces of the bonded semiconductor structure comprises depositing theamorphous film using a chemical vapor deposition process at atemperature of less than 400° C.

Embodiment 6: The method of any one of Embodiments 1 through 5, whereinplanarizing the amorphous film comprises chemically and mechanicallypolishing the amorphous film.

Embodiment 7: The method of any one of Embodiments 1 through 6, furthercomprising:

-   -   heating the portion of the amorphous film within the at least        one recess in the one or more non-planar surfaces at least to a        temperature sufficient to promote recrystallization in the        portion of the amorphous film within the at least one recess in        the one or more non-planar surfaces; and    -   forming one or more device structures on or in the portion of        the donor structure transferred to the processed semiconductor        structure.

Embodiment 8: The method of Embodiment 7, further comprisingelectrically interconnecting at least one device structure of the one ormore device structures on or in the portion of the donor structuretransferred to the processed semiconductor structure with at least onedevice structure of the processed semiconductor structure.

Embodiment 9: The method of any one of Embodiments 1 through 8, furthercomprising:

-   -   transferring a portion of another donor structure to the bonded        semiconductor structure to form another bonded semiconductor        structure that includes one or more non-planar surfaces;    -   forming another amorphous film over at least the one or more        non-planar surfaces of the another bonded semiconductor        structure; and    -   planarizing the another amorphous film to form one or more        planarized surfaces of the another bonded semiconductor        structure comprising:        -   removing a portion of the another amorphous film outside at            least one recess in the one or more non-planar surfaces of            the another bonded semiconductor structure; and        -   leaving a portion of the another amorphous film within the            at least one recess in the one or more non-planar surfaces            of the another bonded semiconductor structure.

Embodiment 10: The method of any one of Embodiments 1 through 9, furthercomprising:

-   -   forming the processed semiconductor structure to comprise a        non-planar major surface and a non-planar lateral side surface;    -   selecting the donor structure to be at least substantially        comprised of a single crystal of semiconductor material; and    -   forming a plurality of device structures on or in the processed        semiconductor structure prior to transferring portion of the        donor structure to the processed semiconductor structure and        forming the bonded semiconductor structure;    -   wherein transferring the portion of the donor structure        comprises transferring the portion of a donor structure to the        non-planar major surface of the processed semiconductor        structure to form the bonded semiconductor structure, the bonded        semiconductor structure having a non-planar major surface and a        non-planar lateral side surface; and    -   wherein forming the amorphous film comprises forming the        amorphous film over the non-planar lateral side surface and the        non-planar major surface of the bonded semiconductor structure.

Embodiment 11: A method of forming a semiconductor structure,comprising:

-   -   forming a plurality of device structures on or in a        semiconductor structure to produce a processed semiconductor        structure comprising a non-planar major surface and a non-planar        lateral side surface;    -   transferring a portion of a donor structure at least        substantially comprised of a single crystal of semiconductor        material to the non-planar major surface of the processed        semiconductor structure to form a bonded semiconductor structure        having a non-planar major surface and a non-planar lateral side        surface;    -   forming an amorphous film over the non-planar lateral side        surface and the non-planar major surface of the bonded        semiconductor structure; and    -   planarizing at least the non-planar major surface of the bonded        semiconductor structure by selectively removing portions of the        amorphous film.

Embodiment 12: The method of Embodiment 11, further comprising selectingthe donor structure to be at least substantially comprised of the singlecrystal of semiconductor material.

Embodiment 13: The method of Embodiment 11 or claim 12, furthercomprising selecting the donor structure to be at least substantiallycomprised of a single crystal of silicon.

Embodiment 14: The method of any one of Embodiments 11 through 13,further comprising selecting the amorphous film to be at leastsubstantially comprised of amorphous silicon.

Embodiment 15: The method of any one of Embodiments 11 through 14,further comprising:

-   -   heating one or more remaining portions of the amorphous film at        least to a temperature sufficient to promote recrystallization        of the one or more remaining portions of the amorphous film, and    -   forming a plurality of device structures on or in the        transferred portion of the donor structure.

Embodiment 16: The method of Embodiment 15, further comprisingelectrically interconnecting at least one device structure on or in thetransferred portion of the donor structure and at least one devicestructure of the processed semiconductor structure.

Embodiment 17: A semiconductor structure, comprising:

-   -   a bonded semiconductor structure having a non-planar major        surface and a non-planar lateral side surface, the bonded        semiconductor structure comprising:        -   a processed semiconductor structure comprising a non-planar            major surface and a non-planar lateral side surface; and        -   a portion of a single crystal donor structure attached to            the non-planar major surface of the processed semiconductor            structure; and    -   an amorphous film disposed over the non-planar lateral side        surface and the non-planar major surface of the bonded        semiconductor structure.

Embodiment 18: The semiconductor structure of Embodiment 17, wherein thenon-planar major surface of the processed semiconductor structurecomprises a plurality of peak regions and a plurality of valley regions,the portion of the single crystal donor structure attached to theplurality of peak regions of the non-planar major surface of theprocessed semiconductor structure.

Embodiment 19: The semiconductor structure of Embodiment 18, wherein theamorphous film is disposed over the plurality of valley regions of thenon-planar major surface of the processed semiconductor structure.

Embodiment 20: The semiconductor structure of any one of Embodiments 15through 19, wherein the single crystal donor structure is comprisedessentially of silicon.

Embodiment 21: The semiconductor structure of any one of Embodiments 17through 20, wherein the amorphous film is comprised essentially ofamorphous silicon.

Embodiment 22: A semiconductor structure comprising:

-   -   a bonded semiconductor structure having a non-planar major        surface and a non-planar lateral side surface, the bonded        semiconductor structure comprising:        -   a processed semiconductor structure comprising a plurality            of device structures, a non-planar major surface, and a            non-planar lateral side surface;        -   a portion of a single crystal donor structure attached to            the non-planar major surface of the processed semiconductor            structure, and        -   a plurality of regions of recrystallized crystalline            material disposed over valley regions of the non-planar            lateral side surface and the non-planar major surface of the            bonded semiconductor structure.

Embodiment 23: The semiconductor structure of Embodiment 22, wherein theplurality of regions of recrystallized crystalline material at leastsubstantially fill recesses in the non-planar major surface of theprocessed semiconductor structure.

Embodiment 24: The semiconductor structure of Embodiment 22 orEmbodiment 23, wherein a plurality of device structures are disposed atleast partially within at least some regions of the plurality of regionsof recrystallized crystalline material.

Embodiment 25: The semiconductor structure of Embodiment 24, wherein atleast one of the device structures disposed at least partially within atleast some regions of the plurality of regions of recrystallizedcrystalline material are electrically interconnected with at least onedevice structure of the plurality of device structures of the processedsemiconductor structure.

The embodiments of the invention described above do not limit the scopeof the invention, since these embodiments are merely examples ofembodiments of the invention, which is defined by the scope of theappended claims and their legal equivalents. Any equivalent embodimentsare intended to be within the scope of this invention. Indeed, variousmodifications of the invention, in addition to those shown and describedherein, such as alternate useful combinations of the elements described,will become apparent to those skilled in the art from the description.Such modifications are also intended to fall within the scope of theappended claims. Headings and legends are used herein for clarity andconvenience only.

What is claimed is:
 1. A method of forming a semiconductor structure,comprising: transferring a portion of a donor structure to a processedsemiconductor structure having at least one non-planar feature andforming a bonded semiconductor structure; forming one or more non-planarsurfaces on a major surface of the bonded structure by forming at leastone recess therein, wherein the at least one recess is formed directlyabove the at least one non-planar feature; then forming an amorphousfilm over at least the one or more non-planar surfaces and into the atleast one recess of the bonded semiconductor structure; and thenplanarizing the amorphous film to form one or more planarized surfacescomprising: removing a portion of the amorphous film outside the atleast one recess in the one or more non-planar surfaces; and leaving aportion of the amorphous film within the at least one recess in the oneor more non-planar surfaces.
 2. The method of claim 1, whereintransferring the portion of the donor structure to the processedsemiconductor structure comprises: implanting ions into the donorstructure to form a zone of weakness within the donor structure; andfracturing the donor structure at the zone of weakness and detachinganother portion of the donor structure from the portion of the donorstructure bonded to the non-planar surface of the processedsemiconductor structure.
 3. The method of claim 1, wherein transferringthe portion of the donor structure to the processed semiconductorstructure comprises transferring discontinuous portions of the donorstructure to the processed semiconductor structure.
 4. The method ofclaim 1, further comprising: heating the portion of the amorphous filmwithin the at least one recess in the one or more non-planar surfaces atleast to a temperature sufficient to promote recrystallization in theportion of the amorphous film within the at least one recess in the oneor more non-planar surfaces; and forming one or more device structureson or in the portion of the donor structure transferred to the processedsemiconductor structure.
 5. The method of claim 3, further comprising:transferring a portion of another donor structure to the bondedsemiconductor structure to form another bonded semiconductor structurethat includes one or more non-planar surfaces; forming another amorphousfilm over at least the one or more non-planar surfaces of the anotherbonded semiconductor structure; and planarizing the another amorphousfilm to form one or more planarized surfaces of the another bondedsemiconductor structure comprising: removing a portion of the anotheramorphous film outside at least one recess in the one or more non-planarsurfaces of the another bonded semiconductor structure; and leaving aportion of the another amorphous film within the at least one recess inthe one or more non-planar surfaces of the another bonded semiconductorstructure.
 6. The method of claim 3, further comprising: heating theportion of the amorphous film within the at least one recess in the oneor more non-planar surfaces at least to a temperature sufficient topromote recrystallization in the portion of the amorphous film withinthe at least one recess in the one or more non-planar surfaces; andforming one or more device structures on or in the portion of the donorstructure transferred to the processed semiconductor structure.
 7. Themethod of claim 6, further comprising electrically interconnecting atleast one device structure of the one or more device structures on or inthe portion of the donor structure transferred to the processedsemiconductor structure with at least one device structure of theprocessed semiconductor structure.
 8. The method of claim 1, furthercomprising: transferring a portion of another donor structure to thebonded semiconductor structure to form another bonded semiconductorstructure that includes one or more non-planar surfaces; forming anotheramorphous film over at least the one or more non-planar surfaces of theanother bonded semiconductor structure; and planarizing the anotheramorphous film to form one or more planarized surfaces of the anotherbonded semiconductor structure comprising: removing a portion of theanother amorphous film outside at least one recess in the one or morenon-planar surfaces of the another bonded semiconductor structure; andleaving a portion of the another amorphous film within the at least onerecess in the one or more non-planar surfaces of the another bondedsemiconductor structure.
 9. The method of claim 1, further comprising:forming the processed semiconductor structure to comprise a non-planarlateral side surface; selecting the donor structure to be at leastsubstantially comprised of a single crystal of semiconductor material;and forming a plurality of device structures on or in the processedsemiconductor structure prior to transferring a portion of the donorstructure to the processed semiconductor structure and forming thebonded semiconductor structure; and wherein transferring the portion ofthe donor structure comprises transferring the portion of the donorstructure to the non-planar major surface of the processed semiconductorstructure to form the bonded semiconductor structure, the bondedsemiconductor structure having a non-planar major surface and anon-planar lateral side surface; and wherein forming the amorphous filmcomprises forming the amorphous film over the non-planar lateral sidesurface and the non-planar major surface of the bonded semiconductorstructure.
 10. The method of claim 9, further comprising selecting thedonor structure to be at least substantially comprised of single crystalsilicon.
 11. The method of claim 9, further comprising selecting theamorphous film to be at least substantially comprised of amorphoussilicon.
 12. A method of forming a semiconductor structure, comprising:forming a processed semiconductor structure to comprise a non-planarmajor surface and a non-planar lateral side surface and forming aplurality of device structures on or in the processed semiconductorstructure; selecting a donor structure at least substantially comprisedof a single crystal of semiconductor material; after forming theplurality of device structures, transferring a portion of the donorstructure to the processed semiconductor structure and forming a bondedsemiconductor structure comprising one or more non-planar surfaces;forming an amorphous film over at least the one or more non-planarsurfaces of the bonded semiconductor structure; and planarizing theamorphous to form one or more planarized surfaces comprising: removing aportion of the amorphous film outside at least one recess in the one ormore non-planar surfaces; and leaving a portion of the amorphous filmwithin the at least one recess in the one or more non-planar surfaces;and wherein transferring the portion of the donor structure comprisestransferring the portion of a donor structure to the non-planar majorsurface of the processed semiconductor structure to form the bondedsemiconductor structure, the bonded semiconductor structure having anon-planar major surface and a non-planar lateral side surface; andwherein forming the amorphous film comprises forming the amorphous filmover the non-planar lateral side surface and the non-planar majorsurface of the bonded semiconductor structure.
 13. The method of claim12, further comprising selecting the amorphous film to be at leastsubstantially comprised of amorphous silicon.
 14. The method of claim12, further comprising selecting the donor structure to be at leastsubstantially comprised of single crystal silicon.
 15. The method ofclaim 14, further comprising selecting the amorphous film to be at leastsubstantially comprised of amorphous silicon.